Nikon Fisheye Converter FC-E9

The Nikon Fisheye Converter FC-E9 consists of the lens and front and rear caps.
See the left image below. The UR-E12 adapter is required to mount the FC-E9
on the 5700 as shown in the right image below.

Here are some important notes:

After mounting this converter, the camera
becomes front heavy (see the right image above). As a result, handle it
carefully with two hands if necessary, and do not pick up the camera
by the lens alone.

Since this lens is heavy, make sure you will hold the camera (and lens)
firmly or use a tripod to minimize camera shake.

The FC-E9 has a very large front element and can
easily invite flare and ghost. Hence, avoid to include a strong light
source in or near your view.

Again, since the front glass element of the FC-E9 is large,
one can easily scratch the surface. Therefore, replace the front cap
when the lens is not in use.

Since the area covered by the flash sensor (and the internal flash)
is blocked partially by this lens, both the internal flash and
external flashes may not work properly. While the internal flash
can fire, it may create a semi-circular shadow in the lower portion
of the image.

Since the FC-E9 has an angle of view of 180 degree, watch out for
those "unwanted" subjects such as tripod legs, your shoes, etc in
the image. Check the monitor to make sure the image only includes
what you want.

Focal Length Coverage

This lens has a magnification of x0.2. When it is mounted, it covers 7mm to
56mm (35mm equivalent). However, the image circle of the FC-E9 does not touch
the upper and lower edges of the image. One must zoom the lens in to about
10.7mm (or 42.1mm, 35mm equivalent) to have a circle touching the upper and lower
edges. In this case, the corresponding 35mm equivalent focal length is 8.4mm.
Fortunately, in doing so will not change the coverage (or angle of
view) of the lens because it simply brings the image circle closer. Zooming the
lens in further to 29.5mm (116mm, 35mm equivalent), a full frame fisheye
image can be obtained. The corresponding 35mm focal length is 23.2mm.

Converter Mode?

No, the 5700 has no special lens mode for the FC-E9. You can just mount the
lens on a 5700 and start shooting. However, due to the very large coverage of
a fisheye lens, you should do the following on your 5700:

Use the close-up (or macro) mode.
In this way, the subject-camera distance can be as close as 0cm (or 0").
However, you should use the monitor or take test shots
to make sure the subjects are in focus.

Use center-weighted or spot metering.
This is especially true if you wish to take circular fisheye images.
In this case, the image circle is only about 59% of the image frame
and the remaining 41% is black. This 41% black area will fool the
matrix metering system to increase exposure, yielding over-exposed
images. However, when you zoom the lens in to take full frame fisheye
images, you can use any one of the three metering modes.

Disable the internal flash.
This is obvious because the internal flash cannot cover 180 degree
in both the circular and full frame fisheye modes. In fact, unless
you are very careful in using multiple external flashes, it is
unlikely that you will get evenly exposed images.

Close-Up

While you might not want to use this fisheye converter for close-up work
because of its distortion, placing this fisheye converter very close
to your subject would get you some very creative and interesting effect
because the foreground is greatly exaggerated.
As mentioned earlier, the shortest camera-subject distance is
0 cm if the camera is in close-up mode.

Circular and Full Frame Fisheye

When the on-camera lens is zoomed all the way out to the 35mm position, the
fisheye converter creates a combined focal length of 7mm covering 183 degree.
The image, however, is a circular one, and does not cover the entire
image frame. The left image below demonstrate this "circular" effect.
Theoretically speaking, only straight lines passing through the center of the
scene can appear as straight lines in the image. Therefore, you should keep
this fact in mind when taking landscape images. The middle image below was
taken by pointing the camera to the left and moving the camera to the right
just a little. As you can see, lines on the ceiling become curvilinear.

When the lens is zoomed in, the image circle becomes larger and eventually
covers the entire image frame. The corresponding focal length of this
full-frame is about 23.2mm (35mm equivalent). Unfortunately, as the on-camera
lens is zoomed in, the angle of view would become slightly smaller and is no
more 183 degree. Therefore, we cannot say
we will have a full-frame fisheye image because a full-frame fisheye should
still have a 180 degree diagonal angle of view. The right image above shows
an example from which you can easily see that the angle of view along the
diagonal of the image is less than 183 degree. Non-linear distortion
still can be seen; but, it is not as dramatic as those in circular fisheye
images.

Technical Data

The following technical information are taken from Nikon's manual.
These information are for the 5700 only.